Hereditary Angioedema (C1 Esterase Inhibitor Deficiency)

Hereditary Angioedema (HAE) is a rare genetic disorder that affects the body's ability to control swelling. It primarily involves the immune system and causes sudden episodes of swelling in various parts of the body, including the hands, feet, face, and airway. This swelling happens because of a deficiency or dysfunction of a protein called C1 esterase inhibitor, which normally helps regulate inflammation. The swelling can be painful and sometimes dangerous, especially if it affects the throat and causes breathing difficulties. People with HAE often experience recurrent attacks that can last several days and may be triggered by stress, trauma, or infections.

Hereditary Angioedema (HAE) is an autosomal dominant disorder characterized by a deficiency or dysfunction of the C1 esterase inhibitor (C1-INH) protein, which is encoded by the SERPING1 gene. This deficiency leads to uncontrolled activation of the complement system and excessive production of bradykinin, a potent vasodilator responsible for increased vascular permeability and localized edema. The hallmark clinical feature is recurrent, non-pitting, non-pruritic angioedema affecting the skin, gastrointestinal tract, and upper airway. Unlike allergic angioedema, HAE does not respond to antihistamines or corticosteroids. The condition is significant due to the risk of life-threatening laryngeal edema causing airway obstruction. Diagnosis is often made in adolescence or early adulthood, with a family history present in most cases.